Thermostat.



No. 646,l00. Patented Mar. 27, I900. c. B. ROGERS.

THERMOSTAT.

(Application filed Oct. 28, 1899.)

(No Model.)

Fig"; 1

Fig". 2.

@Mozmey UNITED STATES PATENT Grrrcs.

CHARLES 1:. ROGERS, or STEVENSON, MARYLAND.

THERMOSTAT.

SPECIFICATION forming part of Letters Patent No. 646,100, dated March2'7, 1900.

Application filed October 28, 1899. Serial No 735,123. (No model.)

To all whom, it may concern.-

Be it known that 1, CHARLES E. ROGERS, a citizen of the United States ofAmerica, residing at Stevenson, in Baltimore county, in the State ofMaryland, have invented certain new and useful Improvements inThermostats, of which the following is a specification.

This invention relates to that class of thermostats in which a balancetilting ther1nome-.

ter closes an electric circuit by its tilting movement caused by theexpansion of the liquid within its tube under the influence of heat andthe resulting change in the center of gravity. Although this device iscapable of being used to regulate the temperature of an inclosure or toperform any similar func tion capable of operation by an electriccircuit automatically closed by the tilting of the thermometer-tubeunder the influence of a change in temperature, as described herein, itis more especially adapted to automatically put into operation asignaling device or alarm whenever the temperature of the inclosurewherein it rests is raised above a given point.

The invention consists of an improved thermostat of the characterhereinbefore referred to and in details of construction, as hereinafterset forth and claimed. Y

In the accompanying drawings, Figure 1 is a perspective view of athermostat constructed in accordance with this invention. Fig. 2 is aperspective view of the device inclosed within a suitable cover.

In the construction of this invention a suitable base or support 1 isemployed, which may be made of metal or any other suitable material,and, as here shown, consists'of an oblong plate or frame provided with abracketpiece2, having suitable holes 3 for screwing the plate 1 to anysuitable support. A thermometer-tube 4 is mounted in a sleeve 5, havingarms 6,which form a shaft with pointed ends 7, resting in supports 8,mounted in the posts or trunnions 9, located on the sides of theplate 1. The thermometer 4 is secured in place by a set-screw 10,clamping the thermometer to the sleeve 5, and may be adjusted to theproper position by loosening the setscrew 10 and moving the thermometer4 through the sleeve 5 and then tightening the screw 10. The supports 8for the arms 6 are preferably arranged to form a delicate bal ance, asshown in the drawings. The normal position of the thermometer 4 ispreferably as shown in Fig. 1, with its bulb 11 resting upon or adjacentto the plate 1. In order to assist and obtain a proper balance of thethermometer 4 on its shaft and to raise or lower the center ofgravity-0f the instrument, as may be desired, a weight 12 is suspendedfrom the lower side of the sleeve 5, and, as here Shown, is in the formof a thumb-screw engaging the sleeve 5, so that the proper position ofthe weight 12 may be obtained by securing it in adjusted position on theunder side of the sleeve 5.

In order to further assist in the balancing of the thermometer, a sleeve13 is employed, preferably located and slidable upon the thermometer 4and held in adjusted position by set screw 14. By loosening theset-screw 14 and moving the sleeve 13 to any point determined upon thesleeve 13 will assist in tilting the thermometer when a certain degreeof heat has been reached on the thermometer-scale by the expansiblefluid in the thermometer. While the adjustment of the sleeve 13determines the degree of heat at which the thermometer shall tilt, thesuspended weight 12, heretofore described, acts to compensate for anyfault in mechanical construction of the instrument or any error in itsadjustment. In lieu of having the sleeve 13 mounted on the thermometer 4it may be mounted and adjustable on the tube 15 and the latter providedwith a graduated scale, which shall indicate the temperature at whichthe Weight of the sleeve, in connection with the expansion' of thefluid, will cause the instrument to tilt and close the electric circuit.

In conjunction with the thermometer 4 is employed a suitable device formore firmly closing the electric circuit and also for holding it inclosed position after the thermometer has tilted. As here shown thedevice preferably consists of a tube 15, supported near one end by meansof a rod 16, mounted on the sleeve 5, and at its other end by means of asleeve 17 engaging the end of the thermon1e' ter 4 and having a contact18, which when the thermometer is tilted contacts with a contactplate 19and closes an electric circuit (not shown) extending through a wire 20,clamped at one end to the terminal 21 mounted on the plate 22, whichsupports the plate 19 and is insulated from the plate 1. The other endof the electrical circuit is connected by a wire 23 with terminal 24,mounted on the plate 1. It will readily be seen that when the contact 18by the tilting of the thermometer 4 cont-acts with the plate 19 thecircuit will be closed through plate 19, terminal 21, wire 23, terminal24, plate 1, supports 0, shaft 6, sleeve 5, rod 16, and tube 15. Inorder to hold the contacts 18 and 19 in closed position after thecircuit is closed by the tilting of the thermometer, a suitableautomatic shifting device is employed, which, as here shown, preferablyconsists of a number of balls 25, located in the tube 15, normally atone end thereof, and when the thermometer 4 is tilted the tube 15,becoming inclined,the'balls 25 roll to the other end of the tube 15 andby their weight hold the contacts 18 and 19 in closed position. Inpractice the device is constructed so that the contact-plate 19 will notpermit the thermometer-tube 4 to descend below a horizontal position inorder to prevent the liquid therein from running to the head of thetube. This inclination, owing to the angle which the tube 15, containingthe sliding Weight 25, bears to the thermometer-tube 4, will besufficient to cause the sliding weight 25 to automatically move to thecontact end of the thermometertube 4 and hold the contact-points 1S and19 firmly together.

In order to protect the thermostat, keep it free from dust, &c., asuitable cover 26 is employed, as shown in Fig. 2, which is placed overthe operative parts and rests on the plate 1. The top of the cover maybe provided with a glass 27 or any suitable covering, by means of whichthe movements of the thermostat may be observed, and in order that theheat may reach and effect the thermometer the plate 1 is provided with anetting or gauze 28 or other suitable open-work whereby the heat mayhave access to the thermometer.

It will thus be seen from the foregoing description that when thetemperature of the room in which the thermostat is located has reached acertain point the expansion of the fluid in the thermometer-tube changesthe center of gravity of said tube and with the aid of the sleeve 13mentioned will cause the thermometer to tilt, bringing the contact 18 incontact with the contact 19 and closing the.

electric circuit, and with the aid of the shifting weights contained. intube 15 keeping said circuit closed, thereby causing any suitable alarmconnected with said circuit to be operated by the closing of saidcircuit.

What I claim is- 1. The combination with an electric circuit of abalance tilting thermometer located in said circuit and adjustablelongitudinally in its fulcrum, an adjustable weight depending from thefulcrum of said thermometer to raise and lower the center of gravitythereof, and an electrical contact at the outer end of said thermometer,which, by the tilting of the thermometer caused by the expansion of theliuid therein, closes an electric circuit, as

herein set forth.

3. The combination with an electric circuit, of a balance tiltingthermometer located in said circuit, and adjustable longitudinally inits fulcrum, an adjustable weight depending from the fulcrum of saidthermometer to raise and lower the center of gravity thereof, and anelectrical contact at the on ter end of said thermometer, which, by thetilting of the thermometer caused by the expansion of the fluid therein,closes the electric circuit, and an automatic shifting weight whichholds said contact in closed position, as herein set forth.

4. The combination with an electric circuit of a balance tiltingthermometer adjustable longitudinally in its fulcrum and located in saidcircuit, and having an electric contact at its 'outer end located insaid circuit, a tube mounted on said thermometer and located in saidelectric circuit, and carrying an auto matically-shifting weight whichholds said contact in closed position when the thermometer is tilted,said thermometer being pr0- vided with a scale and compensating weightmounted upon and adjustable longitudinally on said thermometer, asherein set forth.

In testimony whereof I have signed this specification, in the presenceof two witnesses, this 23d day of October, 1890.

CHAS. B. ROGERS.

\Vitnesses:

CHARLES B. PENROSE, CHARLES H. MILLIKIN.

XIO

